how to use variables in javascript and html code example

Example 1: how to define variable in javascript

var <variable-name>;

var <variable-name> = <value>;

Example 2: html define javascript variable

<script>
var Number = 5;
var String = "Hi!";
var boolen1 = true;
var boolen2 = false;
var array = [11, "Hi!", true];
var object = {age:11, speach:"Hi!", likes_Bananas:true};
</script>